Photographic developer

ABSTRACT

An extended range fast-working photographic developer solution containing a hydroxybenzene compound and a 3-pyrazolidone compound in about a 1:1 weight ratio, and having a highly alkaline pH is disclosed.

Unite States atent 3,192,046 6/l965 Kennard 96/66 3,248,219 4/1966 Jacobs 96/66 FOREIGN PATENTS 893,808 4/l962 Great Britain 96/66 OTHER REFERENCES Journal of Photographic Science, The Simultaneous Developing and Fixing of Photographic Emulsions, Keelan, Vol. 5 (1957) pp. 144- 145i session A6: Theory of Processing, A. J. Axford, pp. 169-172 Primary ExaminerNorman G. Torchin Assistant Examiner-Judson R. Hightower AttorneysHomer 0. Blair, Robert L. Nathans and David E.

Brook ABSTRACT: An extended range fast-working photographic developer solution containing a hydroxybenzene compound and a 3-pyrazolidone compound in about a lzl weight ratio, and having a highly alkaline pH is disclosed.

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ATTOR/VEX PHOTOGRAPHIC DEVELOPER BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to photographic developers and more particularly to extended range, fast working black and white photographic developer solutions.

2. Description of the Prior Art Black and white photographic developers containing mixtures of hydroxybenzene compounds and 3-pyrazolidone compounds are well known in the art. See for example, the following US. patents: DeMarle et al., US. Pat. No. 3,241,967; Levenson et al., U.S. Pat. No. 3,276,874; and Ficken, U.S. Pat. No. 3,284,200. Her'etofore, however, such photographic developers contained substantially greater amounts on a weight basis of the hydroxybenzene compound than the 3- pyrazolidone compound. In example 18 of US. Pat. No. 3,241,967, for example, the developer contains 25.0 grams of hydroquinone and only 1.5 grams of l-phenyl-3-pyrazolidone.

These prior art developer solutions have certain limitations which it has not been possible to overcome to date. One of these limitations is the inability to maintain rated film speeds over a wide gamma range and over a wide range of processing rates.

SUMMARY OF THE INVENTION The invention comprises a new black and white photographic developer. This developer contains a mixture of a 3- pyrazolidone compound and a hydroxybenzene compound in the weight ratio of approximately l/ l. The developer also contains sufiicient alkali to give it a pH in the range of from about 9.5 to about 11.25. 1

This new developer has many advantages over those of the prior art. For example, a wide gamma range can be obtained with a wide range of processing rates without any significant loss in rated film speeds. In aerial reconnaissance, it is important to be able to adjust processing gamma to the leveEs of brightness and reflectance of the scene photographed so that the maximum amount of information can be obtained from the developed photograph. Also, it is much easier to duplicate originals when the originals have optimum gamma.

Higher processing rates are also achievable with the new developer without any significant loss of rated film speeds.

Additionally, the new developer has a long shelf and machine life and is easily mixed because of its simple formula.

Because of its properties, this developer is especially suitable for use in roller transport processing machines. In such use, it has been found that low replenishment rates are sufficient.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The photographic developer described herein is useful for developing exposed silver halide film. Any of the known silver halide films are suitable, such as those with emulsions which contain silver chloride, silver bromide, silver chlorobromide, silver chloroiodide, silver chlorobromoiodide, or silver bromoiodide. This developer is especially efficacious for use with high definition aerial films and most duplicating films.

The hydroxybenzene compounds useful in this invention can contain one or more hydroxy groups. Examples of suitable monohydroxybenzene compounds include N-methyl-paraaminophenol, N-methyl-para-aminphenol sulfate, etc. Preferred hydroxybenzene compounds are dihydroxybenzene compounds with hydroquinone and substituted hydroquinones being especially preferred. Some examples of suitable substituted hydroquinones include alkyl-substituted hydroquinones, aryl-substituted hydroquinones and other hydrocarbon substituted hydroquinones, carboxyl-substituted hydroquinones, acyl-substituted hydroquinones, acyloxy-substituted hydroquinones, alkoxy-substituted hydroquinones, and halo-substituted hydroquinones. Other suitable dihydroxybenzene compounds include catechol and pyragallol.

Examples of 3-pyrazolidone compounds useful in this invention include l-phenyl-S-pyrazolidone, l-p-tolyl-3- pyrazolidone, 5-phenyl-3-pyrazolidone, l-p-chlorophenyl--3- pyrazolidone, l-m-tolyl-3-pyrazolidone, l-phenyl-5-methyl-3- pyrazolidone, l-p-tolyl-5-phenyl-3-pyrazolidone, l-p-methoxyphcnyl-3-pyrazolidone, l-acetamidophenyl-3-pyrazolidone, l-m-aminophenyl-4-methyl-4-propyl-3-pyrazolidone, l-3- acetamidophenyl-4, 4-diethyl-3-pyrazolidone, l-p-tolyl-4, 4- dimethyl-3-pyrazolidone, etc. The particularly preferred 3- pyrazolidone is l-phenyl-3pyrazolidone, which is sold commercially under the trade name Phenidone-A" by Geigy Chemical Corporation.

In the new developer, the 3-pyrazolidone and hydroxybenzene compounds are present in about equal amounts on a weight basis. In general, the weight ratio of the 3-pyrazoiidone to the hydroxybenzene is from about 0.8 to about 1.2, and is preferably about I .0.

The pH is adjusted to be highly alkaline. Sufficient alkali should be added to yield a pH of from about 9.5 to about 1 1.25, and preferably from about 10.5 to about 11.0. Suitable alkaline materials for adjusting pH include sodium or potassium salts of borates, metaborates, phosphates or carbonates.

It is also common practice to add other chemicals to black and white developer solutions. Some examples include: buffers such as the alkaline materials previously mentioned; antioxidants such as sodium or potassium sulfite; fog restrainers such as sodium or potassium bromide; sequestering agents such as sodium tetraphosphate or ethylene diaminetetraacetic acid; etc. Of course, all of the chemicals specifically enumerated herein have many equivalents which can be used in the new developers.

A typical formulation for the new developer solution is:

grams/liter l-phenyl-3-pyrazolidone L8 hydroquinone L8 sodium tetraphosphate 2.0 sodium sulfite 70 sodium metaborate potassium bromide 3 water to one liter pH l I.

grams/liter J-pyrazolidone 2.75:1.0 hydroquinone 3911.0

alkali to pH 9.5-H15.

In addition, replenishment solutions usually contain sequestering agents, buffers, antioxidants and fog restrainers. A typical replenishment solution of this invention contains:

grams/liter l-phenyl-B-pyrazolidone 2.75 hydroquinone 3.90 sodium tetraphosphate 2.0 sodium sulfite 85.0 sodium metaborate I001) water to one liter.

Replenishment rates are relatively low. Characteristic values are about 20 ml./ sq. in. film processed to an approximate density of L0 on original negative films, and about 10 ml./100 sq. in. film processed to an approximate density of l .0 for duplicating films.

The invention is further illustrated by the following examples.

EXAMPLE 1 Four strips of Eastman Kodak Punatomic-x Aeriul (3400) film were exposed with a Kodak 1B Sensitometer for an exposure time of 0.02 seconds using a lamp number 431-3513 and a Coming 5900 filter. The exposed films were processed in a Kodak Versamat ll CM(EH-38A) Processor at a machine speed of feet per minute using two development racks. Under these conditions, development time was 26 seconds.

Each film strip was processed with a different developer solution. The first strip was processed using a starter developer solution according to this invention which had the following composition:

Quadrafos 2.0 grams l-phenyl-3pyrazolidone (Graphidone A) 1.8 grams Hydroquinone 1.8 grams Sodium Sulfite 75.0 grams Sodium Metaborate 75.0 grams Potassium Bromide 3.0 grams Water to one liter A replenisher solution having the following composition was supplied at the rate of about 20 milliliters per 100 square inches of film processed to a density of approximately 1.0:

Quadrafos 2.5 gram l-phenyl-3pyrazolidone (Graphidone A) 2.75 gram Hydroquinone 3.9 grams Sodium Sulfite 85.0 gram 5 Sodium Metaborate 100.0 gram Water to one liter The other film strips were processed with the commercially available developers listed below. The results were: I

AEI Developer Temp. Speed Fog Gamma LNew 85" F. 17 0.l2 1.2 2. Hunt 85 F. 4.7 0.07 2.4 Chemical Aeroflo 3. DuPont 90 F. 3.6 008 1.0

SC-OlO 4. Eastman 85 F. It) 0.09 2.0. Kodak MX-64l Sensitometric data obtained from the processed films are plotted as D log E curves in FIG. 1.

As can be seen, the new developer resulted in greatly increased film speeds while maintaining gamma and fog at low levels.

Similar increases in film speed were obtained using identical processing conditions with a variety of films as shown below:

Kodak High Definition Aerial Film (3404) AE] Developer Temp. Speed Fog Gamma 1. New 85 F. 1.6 0. 1.8 2. Hunt 85 F. 0.54 0.08 1.0

Chemical Acroflo" 3. DuPont 90 F. 0.40 0.08 1.0 SC-(llO 4. Eastman 85 F. 1.0 0. ll 2 Kodak MXfiAl Kodak Plus-x Acrographic Film (2402) AE! Developer Temp. Speed Fog Gamma The wide range of gammas obtainable with the new developer solution without any serious loss in film speed is illustrated by this example.

The exposure, processing machine and processing conditions are the same as for the first film strip used in example 1. Kodak Panatomic-x Aerial Film (3400) is processed at F. with a dryer temperature of 140 F. to obtain the results shown in table 1. The data obtained are plotted as D log E curves in P16. 11.

TABLE I Develop- A El Machine speed Developer ment time, spend (feet/min.) racks seconds G ammo (0.6 gammal 1 Equivalent, 3G fret/min, 2 racks.

EXAMPLE lll Eastman Kodak Fine Grain Aerial Duplicating film (2430) was exposed using a Kodak 1B Sensitometer for 0.1 sec. to a tungsten lamp. The exposed film was processed on the Versamat processor of example 1 and the new developer solution of example 1 was used to process the film at 85 F. The results illustrate further the wide gamma range which can be obtained without any serious loss in film speed. The data obtained are shown in table 11.

TABLE 11 Develop Machine speed (fcct/ Developer time. min.) racks seconds (lamina 1/15 spool .2 102 2 51 2. (1 0. 23 2 3 1. .1 0. 20 .2 2G 1. 7 ll. 17 1 l7 1 0 0.10

1 Equivalent, 30 font/min, 2 racks.

EXAMPLE IV The procedure of example 111 was repeated with Kodak High Definition Aerial Film (3404) except that exposure was through a Coming 5900 filter and processing was carried out at F. The data obtained are shown in table 111.

TABLE 11! Develop- AEl int-.nt Spootl Machine speed Dovelopur time, (0.6 (loot/min.) racks seconds Gamma gamma) 1 51 .2 2 l,l 1 25 l. 5 1. 7 1 17 l. 3 1. 4i 1 13 1 l l. 5

EXAMPLE v The versatility and high speeds obtainable with the new developer solutions are further illustrated by this example. For comparison, results obtained with other commercially available developers are included. Processing was accomplished using the machine and procedure of example 1, subject to the conditions stated herein.

The new developer solution had the composition as shown in example 1. The data obtained are shown in table IV.

6. A photographic developer of claim 5 wherein said 1- phenyl-3-pyrazolidone and said hydroquinone are present in a weight ratio of about 1:1.

7. A photographic developer of claim 6 wherein said developer also contains a fog restrainer.

8. A photographic developer of claim 7 which also contains an antioxidant.

9. A photographic developer of claim 8 wherein said alkali 10 is present in an amount sufficient to produce pH of about 1 l in TABLE IV. AEl SPEEDS Rated AEI speed Maohinu speed (IL/min.)

Film type Racks Kodak Panatomic-X Aerial l0 Kodak PlusX Aerial (3401) Kodak Iligh Definition Aerial Kodak Double-X Aerographic Kodak Plus X Aerographic Kodak Aerograpliic Duplicating (2420) Kodak Fine Grain Aerial Duplicating (2430) 1 vtetctotowmwwwrtotololcwwtommwlowlQtoHwloNwHwmwlQ l 1/E speeds. 2 Values obtained are for 1 developer rack at 5-10-15-20 f.p.n1.

What is claimed is:

l. A variable gamma, fast working, black and white photographic developer containing a mixture of at least one 3- pyrazolidone compound and at least one hydroxybenzene compound, said 3-pyrazolidone compound and said hydroxybenzene compound both being present in an amount of 1.8:1 .0 grams per liter of developer solution, and the weight ratio of said 3-pyrazolidone to said hydroxybenzene compound being from about 0.8 to about 1.2, said developer also containing sufficient alkali to produce a developer pH of from about 9.5 to about 11.25.

2. A photographic developer of claim 1 wherein said hydroxybenzene compound comprises a dihydroxybenzene compound.

3, A p lgatographic deve lop er of claim 2 wherein said dihydroxybenzene compound comprises hydroquinone.

4. A photographic developer of claim 3 wherein said 3- pyrazolidone compound comprises l-phenyl-3-pyraz olidone.

5. A photographic developer of claim 4 wherein said alkali is present in an amount sufficient to produce a developer pH of from about 10.5 to about 11.0.

New Developer Hunt. (luuuioul rug. Arrollo, 110 1'.

hu lout S0 010, 90 F.

said photographic developer.

10. A photographic developer of claim 9 wherein said alkali comprises sodium metaborate and is present in amount of from about 30 to about 1 10 grams per liter of photographic developer solution.

11. A photographic developer replenisher containing the following, based on 1 liter of aqueous solution:

l-phenyl-3-pyrazolidone hydroquinone alkali to pH about 9.5-1 1.25.

about 2.75 grams about 3.9 grams 12. A photographic developer replenisher of claim 11 having the following formulation:

grams/liter 1-phenyl-3-pyrazolidone about 2.5 hydroquinone about 3.9 sodium tetraborate about 2.5 sodium sulfite about 85 sodium metaborate about 100 water to 1 liter. 

2. A photographic developer of claim 1 wherein said hydroxybenzene compound comprises a dihydroxybenzene compound.
 3. A photographic developer of claim 2 wherein said dihydroxybenzene compound comprises hydroquinone.
 4. A photographic developer of claim 3 wherein said 3-pyrazolidone compound comprises 1-phenyl-3-pyrazolidone.
 5. A photographic developer of claim 4 wherein said alkali is present in an amount sufficient to produce a developer pH of from about 10.5 to about 11.0.
 6. A photographic developer of claim 5 wherein said 1-phenyl-3-pyrazolidone and said hydroquinone are present in a weight ratio of about 1:1.
 7. A photographic developer of claim 6 whereiN said developer also contains a fog restrainer.
 8. A photographic developer of claim 7 which also contains an antioxidant.
 9. A photographic developer of claim 8 wherein said alkali is present in an amount sufficient to produce pH of about 11 in said photographic developer.
 10. A photographic developer of claim 9 wherein said alkali comprises sodium metaborate and is present in amount of from about 30 to about 110 grams per liter of photographic developer solution.
 11. A photographic developer replenisher containing the following, based on 1 liter of aqueous solution: 1-phenyl-3-pyrazolidone about 2.75 grams hydroquinone about 3.9 grams alkali to pH about 9.5-11.25.
 12. A photographic developer replenisher of claim 11 having the following formulation: grams/liter1-phenyl-3-pyrazolidone about 2.5 hydroquinone about 3.9 sodium tetraborate about 2.5 sodium sulfite about 85 sodium metaborate about 100 water to 1 liter. 